Exchange rates

12 Months Ended

Dec. 31, 2022

Text Block [Abstract]

Exchange rates

1. Exchange rates

	2022				2021				2020
$1 equivalent	Average		Closing		Average		Closing		Average		Closing
Sterling		£0.81		£0.83		£0.73		£0.74		£0.78		£0.73
Euro		€0.95		€0.94		€0.85		€0.88		€0.88		€0.81